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Promethean Air Cleaner - Sourcing & Build Guide

Last Updated: August 30th, 2022

Active WIP as of 8-30-2022

This unit is in no way a replacement for proper ventilation that is HIGHLY recommended in any resin setup - it is supplemental to a setup by assisting to contain 'fumes' at the source. Follow the links for Ventilation Simulations - Safety FAQ - Example Safety Equipment

The Promethean air cleaner is designed for FDM and resin 3D printing. This air cleaner pulls air through a MERV 13 filter and activated carbon granules. The MERV 13 filter is ideal for capturing nanoplastics generated from FDM printers. The activated carbon mitigates fumes from FDM and resin printers - place emphasis on mitigation since carbon typically has efficiencies of 40-60%

The Promethean files are released for non-commercial use (don't make and sell these) and a sourcing & build guide is provided below. If you wish to purchase a pre-assembled version or pick up some of the components, head over to our Promethean product page.

Table of Contents

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Free Flow Rate 28-63 cfm
MERV 13 Filtration Rate 13-38 cfm
MERV 13 + Carbon Rate 11-27 cfm
Grate Face Velocity 160-350 fpm
Duct Face Velocity 350-850 fpm
Sound Level @ 1m (3ft) 41-68 dB
Sound Level @ 3m (9ft)
38-64 dB
Dimensions 8.8x6.6x6.3 in
Supply Voltage 12 V
Power Consumption 2.6-18.4 W

*Specs based off a 120 mm, 178 CFM, 0.94 inH2O, 4,200 RPM, ≈18 W DC fan.

DIY - Free

  • Download STLs & print off the files
  • Source 120 mm fan
  • Optional PWM module
  • Source AC-DC adapter
  • Source MERV 13 filter & Optional foam seal
  • Print/Source reusable cartridge & Source activated carbon
  • Optional duct hose & adapters

Assembled - $150

  • Unit arrives prebuilt with parts
  • Includes 120 mm fan
  • Includes PWM module for fan speed control
  • Includes 12 VDC, 24 W AC-DC adapter
  • Includes MERV 13 filter (x1) & foam seal
  • Includes reusable cartridge & activated carbon (320 g)
  • Includes duct hose (4 ft) & adapters

Promethean Component Sourcing

Required? Category Component Specification Quantity Source 1 Source 2 Source 3
Required 3D Print Housing & Accessories
Required 3D Print Filament PLA Recommended ≈600 g Prusament Eryone Polymaker
Required Electronics 120 mm Fan 12 VDC 1 4D (Ebay) AliExpress1 Amazon1
Optional Electronics PWM Module 12 VDC - 3 A Max 1 4D
Required Electronics AC-DC Adapter 12 VDC - 24 W 1 4D (Ebay) Amazon2 Mousers2
MERV 13 Filter
6 x 6 x 1 in (150x150x25mm) 1 4D 4D (Ebay) Home Depot3
Optional Filtration Filter Foam Seal 1/2 x 1/16 in (12.7x1.6 mm) 24 in McMaster Amazon AliExpress4
Required Filtration Carbon Cartridge Option #1 - Buy 1 4D
Required Filtration DIY Cartridge - Resin Option #2 - Build ≈120 g
Optional Filtration Cartridge Seal - Silicone Comes with cartridge 1 4D
Optional Filtration Housing EPDM Seal 1/16 in (1.78mm) Diameter  in McMaster Amazon
Required Structural Fan Screws #4-40 (M3) 2 in 4 Bolt Depot
Required Structural Fan Hex Nuts #4-40 (M3) 4 Bolt Depot
Required Structural Lid Screws #4-40 (M3) 1/2 in 3 Bolt Depot
Required Structural Lid Heat Inserts #4-40 (M3) 3 McMaster Amazon AliExpress5
Optional Misc Magnets 1/4 x 1/4 x 1/8 in (6x3mm) 4 Applied Magnets McMaster Amazon6
Optional Misc Felt Discs 1/2 in Diameter, 1/8 in Thick 8 McMaster Amazon
Optional Misc Duct Hose 4 in Diameter (100mm) 3 ft+ Lambro (Amazon) AC Infinity (Amazon) Vivosun (Amazon)
Optional Misc Zip Ties 16 in (400mm) 2 Amazon AliExpress7
  1. The 120 mm fan can be AC or DC, any thickness, 2-4 wire, and any voltage. The 38 mm thickness fans are generally designed for higher static pressure, which is needed to pull air through filter media. Any 2-wire fan is acceptable, but 4-wire fans can be controlled with PWM. The voltage can be whatever you would like, but it does need to match the power supply - 12 VDC is recommended due to the wide availability of components.
  2. Make sure that the power supply matches the voltage and is rated for the wattage of the fan.
  3. Small MERV and HEPA panel filters are uncommon. To our knowledge, we sell the highest-rated MERV 6 x 6 x 1 filter. There are MERV 7 and 9 filters of this size on Amazon and McMaster, but the efficiencies of these panels are substantially lower than MERV 13. You have the option of taking larger panels and cutting them to size - if you do this, the filter needs to be sealed properly. We use MERV instead of HEPA by default since it allows for more airflow, allowing use as a normal air cleaner and a fume extractor. HEPA filter media can be more efficient if the primary use is as a fume extractor.
  4. Not Internally Tested - "T2mm x W15mm" should be the most appropriate. These metric-sized adhesive foam strips are just slightly thicker than their imperial counterparts.
  5. Not Internally Tested - using M3 screws, nuts, and heat inserts is perfectly fine, just make sure to match the components.
  6. Not Internally Tested - imperial or metric disc magnets can be used, but they may need a very small amount of adhesive to prevent sliding or ejection.
  7. The "5x400mm" zip ties are an appropriately sized substitution. Zip ties used to secure the duct to adapters.

Promethean 3D Printed Parts

Required? Component Quantity Estimated Material
Required Housing 1 400 g
Required Front Lid 1 60 g
Required Back Lid 1 40 g
Optional Grate 2 20 g
Optional Grate Duct Adapter 1 50 g
Optional External Duct Adapter 1 25 g
Cartridge Funnel 1 7 g
Optional PWM Hex Tool 1 3 g
Required if DIY DIY Carbon Cartridge 1 120 g (resin)

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How To Build The Promethean Air Cleaner

Promethean Parts1
Promethean Parts2

Printing The 3D Parts

  1. To make the printing experience as easy as possible, we have supplied 3MF and GCODEs for each part. We Highly Recommend using PrusaSlicer and loading the 3MF files into the software to have  optimized settings.
    The GCODEs use a nozzle temp of 215°C for PLA and 240°C for PETG.
    3D Files
  2. Most of the prints are fairly quick, but the housing is quite large and will take ≈30 hours. We recommend sticking with PLA and having an enclosure to minimize warping on corners. Any warping that does occur typically is small and should not affect the functionality of the air cleaner. We recommend using a build plate adhesive like Vision Miner's Nano Polymer Adhesive (Amazon Link) on the corners of the print to eliminate warping.
    Minimize Warping
  3. The carbon cartridge is printed on a medium-sized resin printer due to the complex geometry and size - there are nearly 7,000 hexagonal holes to allow airflow. This STL can be inserted into a resin slicer like Lychee or Chitubox. The cartridge should be printed directly on the built plate. The cartridge is chamfered on the bottom to mitigate elephants foot and make removal easier.

    Currently, we recommend using a durable resin for the cartridge - brittle resin will likely break during removal from the plate or during cleaning.

    The layer cure time should be 20%+ higher than normal to ensure rigidity while printing. For example, on an Anycubic Mono X at 80% UV power, SuperPP prints well at 1.3-1.6 s per layer at 30°C with a base layer time of 4 s and a lift speed of 30-60 mm/min. You can use similar settings on most monochrome printers.
    P Mini in the slicer software
  4. The carbon cartridge, depending on the resin and settings used, can be delicate - it should be carefully removed and handled while cleaning. For removal, you can start by scraping/lifting the print from a corner and working towards the middle. This can be one of the harder prints to remove.

    The recommended method of cleaning is squirting or a quick dip in clean IPA followed by ≈1 minute in an ultrasonic cleaner. If you do not have an ultrasonic cleaner, then the squirting/dip will need to be repeated several times.

    A fan, hair dryer on low heat, or compressed air can be used to remove the cleaner/solvent from the mesh. You may need to repeat the cleaning and drying process a few times to remove all of the uncured resin. Do not use a heat gun as this can warp and melt the mesh.

Installing Heat Inserts

  1. Take a heat insert and place it upright on the three housing holes.
  2. Use a fine-tip soldering iron to push the inserts into the housing - be quick so as not to overheat the plastic.
    Installing Heat Inserts
  3. Make sure the inserts are flush or below the housing. While hot, you can use one of the long screws to align the inserts if needed.
    P Mini blower fan wire orientation

Installing Magnets

  1. Take an exacto knife or flat head screwdriver and clear out any overhangs inside the magnet slots on the housing.
    Clearing Debris
  2. Place two magnets inside of the housing slots. You can use a flat head screwdriver to help push the magnet inside. If the magnets you are using are undersized, it is recommended to use a small amount of adhesive to prevent sliding or ejection. We like using Gorilla Super Glue Gel.
    Installing Magnets on Housing
  3. Identify the polarity of the remaining two magnets by placing them on top of the housing magnets. These should be placed inside the front lid in the orientation where they attract. This will keep the lid down during use without the need for screwing on the lid.
    Installing Magnets on Lid

Installing Housing Seals

  1. Take one end of the EPDM cord stock and place it into the long housing slot. Use an exacto knife or scissors to cut the cord, The recommended cord stock should be snug - adhesive can be used to secure the cord in place. Repeat this for the other side.
    Installing Housing Seals1
  2. Take the remaining cord stock and place it into the smaller perpendicular sections. The cord stock will help prevent air from entering through the lid.
    Installing Housing Seals2

Installing Felt Discs

  1. Take four of the felt discs and place them along the fan mount. These provide light vibration suppression.
    P Mini blower fan wire orientation
  2. Take the remaining four felt discs and place them at the bottom of the housing.
    P Mini blower fan wire orientation

Installing The PWM Module

  1. The PWM Module has orange buttons that release a spring slot for the wire to slide into. Wire the fan leads into the PWM module as shown - from left to right: black (negative), red (positive), yellow (signal), and blue (pwm).
    PWM Wires
  2. Take off the hex nut and washer then slide the module into the housing.
  3. Place the washer and hex nut back onto the rotary knob from outside the housing. Secure the hex nut with the 3D printed hex tool. Finally, slide the cover onto the rotary knob.
    Power Knob Cover

Mounting The Fan

  1. Place the four hex nuts into the slots on the front of the fan mount as shown.
    Inserting Hex Nuts
  2. Orient the fan with the label towards the rear of the air cleaner - the air comes out this side. If you want to double check, you can plug the fan in to determine the correct orientation. If the fan leads are too long, you can trim them down or rotate the fan 90°.
  3. Place the four long screws into the fan and into the mounting holes. Do not overtighten the screws as it can bend the plastic. The plastic won't break but it will result in misalignment of the front lid's screw mount.
    Installing the Fan

Filling The Carbon Cartridge

  1. Take the cartridge and fill it up with carbon using the funnel or straight out of the bag. All of the holes should be covered with carbon. You can place a paper towel or plate under the cartridge while filling in case some carbon spills.
    Filling the Carbon Cartridge
  2. Place the silicone seal on top of the cartridge walls and make sure the corners are flush.
    Cartridge Seal
  3. Slide the carbon cartridge into the rear slot of the housing. The activated carbon will capture a reasonable percentage of 'resin fumes' and VOCs from FDM printers.
    Cartridge in Housing

Installing The Particulate Filter

  1. After removing the filter from the packaging, take the adhesive-backed foam strip and wrap it around the filter. Tear off any excess foam.
    Foam on Filter
  2. Place the particulate filter in the front slot of the air cleaner. The MERV 13 filter will be ideal for capturing the majority of nanoplastics generated from FDM printers.
    Filter in Housing

Finishing Up

  1. Place the two grates into the front and rear slots.
    Grates in Housing
  2. Take two of the short screws and secure the rear lid.
    Installing the Back Lid
  3. The third screw for the front lid is optional but will absolutely prevent it from opening.
    Installing the Front Lid
  4. Plug in your 12 V AC-DC power adapter and you are good to go!
    Power Adapter

Optional: Duct Hose

  1. Cheap duct hose is typically made of vinyl and should not be used for high-temperature applications. Heat-resistant and metal duct hose should be used for this.
  2. The grate duct adapter can replace the front grate. The duct hose can be slid over this adapter and secured with a zip tie. Trim down the zip tie.
    Foam on Filter

  3. The other end of the duct should be hooked up to the printed external adapter, your own custom adapter, or any standard 4" duct attachment. The duct can be hooked up to grow tents.
    Foam on Filter

Experimental: Single Slot Carbon Cartridge

  1. The optimized carbon cartridge is pleated, thus it must be printed with resin. This single slot version is intended to be printed on a FDM printer. While this version will work, it will result in a lower process rate and efficiency.
  2. After the three pieces are printed, adhesive should be placed on one half before pressing/clamping the two sections together.
    Placing Adhesive

  3. Fill the cartridge with carbon, covering all of the mesh.
  4. Bend the lid into the cartridge and place the assembled component into one of the air cleaner slots.
    Inserting the Lid

New User Checklist

  1. Remove the center screw from the top lid and slide the lid back - do not lift up. This screw is optional since the lid is magnetic.
    Placing Adhesive

  2. Remove the particulate filter from the packaging. Peel off the adhesive backing from the foam and wrap it around the filter frame. Tear or cut off any excess foam. Place the filter in the front slot.
    Placing Adhesive

  3. Take the cartridge and fill it up with carbon using the funnel or straight out of the bag. All of the holes should be covered with carbon. You can place a paper towel or plate under the cartridge while filling in case some carbon spills.

    Slip the silicone seal back onto the cartridge, making sure the corners are flush. Place the cartridge into the rear slot.
  4. Slide the lid back on - use the screw if you wish. Plug the power in and turn the knob to adjust the speed. You're good to go!
  5. If you wish to use duct, replace the front grate with the appropriate adapter. Slide the duct over the adapter and secure it with a zip tie. Use clippers or scissors to trim the tie down.

    The other end of the duct can be attached to a grow tent, a standard 4" connection, a custom adapter, or the provided external adapter (which can be screwed or glued onto an enclosure, panel, or wall).

Ultimate Resin Guide - compare resin printers, resin material, and equipment

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FDM Printers Guide - comparison table and top picks for filament printers

Resin Properties or Filament Properties - comparison table and top picks for materials

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